Mikvaos, Chapter 10, Mishnah 3. This chapter is built around the requirement of bi'as mayim: when something is immersed in a mikvah, the water must reach every part of it. The question our Mishnah addresses is what to do about places that are ordinarily closed off. Specifically, it deals with knots. A knot pulled tight will keep the mikvah water from reaching the fabric or leather beneath it. Must such a knot be undone before tevilah?
The answer depends on the nature of the knot. If a knot is tied in a way that it is meant to stay, and that is simply how the item is kept and used, then the spot underneath it is not considered a place that needs the water. The keli or garment is being immersed exactly as it exists in its normal state.
The Mishnah now presents a heading for the cases it is about to enumerate, announcing that in the following instances there is no obligation for the mikvah water to make its way inside.
The knots that may be left tied
- "Kishrei he'ani": the knots of a poor man. His clothing has torn, and rather than mend it he ties the pieces together. Those knots are there to stay.
- "Vehanimin": knots tied on the fringes and threads at the edges of various garments and hangings.
- "Vechavat shel sandal": the knot made on the strap of a sandal so that the strap should not slip back out of its hole. This too is a kesher shel kayama, a lasting knot.
Since each of these knots is made in order to remain permanently tied, the water need not be able to penetrate beneath it.
The knots of tefillin
"Tefilah shel rosh, bizman shehi chagurah": the knot of the tefillin shel rosh, the one seated at the nape of the neck when the tefillin are worn, may be left as it is, provided it is drawn snug and the wearer does not plan on slackening it. "Veshel zero'a, bizman she'einah olah veyoredes": as for the tefillin shel yad, the condition is that its knot be set so tightly that it cannot slide upward or downward along the strap. A knot fastened that immovably onto the tefillin is regarded as one made to last.
Leather bags and their straps
"Oznei hachemes": the leather straps that serve as the handles of a chemes, the leather water skin or canteen, tied onto the pouch. "Ve'oznei haturmal": and the handles of the turmal, the shepherd's leather bag. Here too the knots are tied with the intention that they stay in place for good.
The thread running through the entire Mishnah is a single idea: a knot that is made to remain is part of the item as it stands. When such a garment or vessel requires tevilah, its knots need not be loosened or untied, and the water need not reach the fabric or leather hidden beneath them.